This is a talk given at the Redwood Center for Theoretical Neuroscience, UC Berkeley on
January 23, 2007. Speaker is Giuseppe Vitiello, Department of Physics “E.R.Caianiello”, Salerno University.
Title: Relations between many-body physics and nonlinear brain dynamics
In a recent paper  it has been proposed a many-body model of nonlinear brain dynamics based on the thesis that mammalian neocortex supports dynamics sufficiently similar to the one of cooperative domains, such as cooperative domains in spin glasses, ensembles of phonons in crystals, coherent photons in lasers, condensation of vapors in crystal formation, etc., to warrant exploration of neurophysiological data and models in terms well-known by physicists. Our approach is evolving from the quantum field theory model proposed in 1967  by Umezawa and Ricciardi where the mechanism of spontaneous breakdown of symmetry was proposed to be the basic mechanism originating brain functions such as memory recording and recall. By considering the fact that brains are open, dissipative systems that consume free energy in creating large-scale behaviorally related spatiotemporal patterns, we extend the Umezawa-Ricciardi model to dissipative dynamics, thus relating microscopic many-body dynamics to Prigogine's nonequilibrium thermodynamics and Haken's synergetics. Much attention is devoted in our model to the connection between specific features of the many-body dynamics, characteristic of the theory of quantum fields, and the rich phenomenology of neurophysiological data. We compare and contrast ECoG pattern formation in neocortex in terms of phase transitions in classical physics and spontaneous breaking of symmetry in quantum physics. A novel perspective in brain dynamics seems to emerge, unifying brain studies and condensed matter physics.
 Freeman WJ, Vitiello G (2006) Nonlinear brain dynamics as macroscopic manifestation of underlying many-body field dynamics. Physics of Life Reviews 3: 93-118. http://dx.doi.org/10.1016/j.plrev.2006.02.001, http://repositories.cdlib.org/postprints/1515, http://arxiv.org/q-bio.OT/0511037
 Ricciardi L M, Umezawa H(1967) Brain physics and many-body problems. Kibernetik 4: 44-48.
Kilian Koepsell Redwood Center for Theoretical Neuroscience University of California Helen
Wills Neuroscience Institute 132 Barker, MC #3190 Berkeley, CA 94720-3190